Conventionally, polyester multi-filament yarns have been used unlike other synthetic fibers such as nylon or acryl because the polyester multi-filament yarns can impart excellent drape property to a woven fabric and can express en elegant silhouette particularly in female dresses.
To impart the drape property, hard twist must be applied to the polyester multi-filament yarn. The yarn is then woven, and the resulting grey goods is subjected to alkali weight loss in a dyeing process and a woven fabric is obtained.
The application of hard twist not only imparts the drape property to a woven fabric but also provides the effects of eliminating a conventional waxy feeling of the woven fabric and imparting a dry and harsh and stiff(shari) feeling. This harsh and stiff(shari) feeling is different depending on the number of hard twists and when the number of twists is excessively great, feeling becomes hard and the woven fabric comes to have an undesirable hard and sandy(jyari) feeling.
When hard twist is applied to the conventional multi-filament yarn so as to impart the drape property or the harsh and stiff feeling, the multi-filament yarns are highly bundled, and the resulting woven fabric comes to have a hard feeling not having a puff property and soft feeling due to the twist structure. To solve this problem, Japanese Patent Publication Nos. 19733/1986, 31210/1986 and 61422/1988 propose a multi-component structure false-twist textured yarn having a core-sheath two-layered structure by compositing at least two kinds of multi-filament yarns having different elongations and drawing and false twisting them.
This structure of the composite structure false twisted finished yarn forms a two-layered structural form having a difference of yarn lengths between core yarns and sheath yarns. In the additional twist process, therefore, a twist yarn tension is first applied to the core yarn side having a smaller yarn length and twist is imparted under a bundled state. As the number of twists further increases, twist is gradually imparted to the group of multi-filaments on the sheath side, and the yarns are twisted around the core yarns. Accordingly, even when the number of twists increases, the multi-filament yarns on the sheath side can form gaps and tend to possess a puff property and a soft feeling.
On the contrary, because the drape property is not sufficient, the woven fabric is not satisfactory. To obtain the drape property or the dry feeling, the number of hard twists must be further increased, so that the drop of the puff property and the soft feeling due to the increase of the number of twists is invited. This problem is remarkable particularly in medium thick woven fabrics using the finished yarns.
As described above, when twisting is effected in the conventional polyester multi-filament yarn or the multi-component structure false-twist textured yarn having the core-sheath two-layered structure so as to obtain the drape property and the dry and harsh and stiff(shari) feeling, the puff property and the soft feeling drop, and when the puff property and the soft feeling are sought, the drape property and the dry feeling drop. it has therefore been difficult to obtain a woven fabric which has the drape property, the dry feeling, the puff property and the soft feeling.
On the other hand, the polyester multi-filament knitted/woven fabric which is recently referred to as the "new synthetic fiber", so called "Shin-Go-Sen" has a new feeling of good quality which is peculiar to the polyester and cannot be expressed by natural fibers, and when the knitted/woven fabric is touched, the fiber accomplishes a new feeling different from the conventional feeling. However, it involves the problem that when the fiber is put on as a dress, its hygroscopicity and water absorption are by far lower than those of the knitted/woven fabric obtained from the natural fibers.
Though various examinations have been made so as to improve hygroscopicity and water absorption of the synthetic fiber, the synthetic fibers yet involve the problems in comparison with the natural fibers.
In the case of the polyester multi-filament yarns, hygroscopicity has been improved by graft polymerization, mixing of a material having hydrophilicity or copolymerization, and as to water absorption, a method which improves water absorption by utilizing the capillary phenomenon in the aggregate of the multi-filament due to their sectional shapes has been proposed in Japanese Patent Laid-Open No. 122074/1980 besides the technologies described above.
As described above, however, when additional twist is applied to the polyester multi-filament yarn as high level processing means for imparting the new feeling of good quality peculiar to the polyester, protuberances and recesses of the multi-filament yarns having different sectional sections according to the prior art engage with one another as a result of hard twist and the multi-filament yarns are thus packed. Accordingly, the gap structure disappears and the water absorption affect due to the capillary phenomenon cannot be obtained.
Japanese Patent Publication No. 27608/1973, etc, proposes a method which effects spinning after mixing an alkali-soluble material, accomplishes a porous structure by an alkali weight loss of the woven fabric and thus imparts the water absorption property. However, in this case, too, when hard twist is applied, the multi-filament yarns are packed, and water absorption of the gap structure by the capillary phenomenon contributes only to the surface portion of the fiber. Accordingly, water absorption drops remarkably in comparison with the case where twist is not applied. For this reason, the feeling under the water retention state is not free from the wet and gooey(betotsuki) feeling.
Further, in order to impart the water absorption effect, the alkali weight loss is essentially necessary, and the problem of acquisition of water absorption exists in the application for water absorption in the field where additional twist is necessary or in the field where the alkali weight loss is not necessary.